Feed horn type RF antenna devices typically have internal air volumes associated with the feed horn. For example, an air cavity typically exists within the interior of a feed horn. This interior space can be typically connected to a waveguide cavity. The feed horn can further be covered with an aperture close-out and otherwise sealed to keep moisture out of this interior space.
If the pressure inside this interior air volume increases sufficiently, however, it is possible that the aperture close-out or other seals could rupture or be degraded to the point that moisture can enter the RF device. As discussed herein, moisture within the internal air volume of feed horn type RF antenna devices can significantly degrade the performance of the RF device. To illustrate this point, FIG. 9 illustrates the severe impact of one drop of water placed in each of 8 ports of an 8:1 RF combiner. As can be seen, there can be relatively little difference between the performance of a dry waveguide and a waveguide with water at the flange interface. However, the performance can be severely degraded if water is located near the power dividers where RF current densities can be the highest. This can be particularly true in Ku and Ka band frequency RF devices. In smaller, single feed horn RF antenna devices, it may be possible to minimize the total internal air volume such that sealing the device may work. However, sealing an antenna device can be less of an option in larger systems and systems that operate in changing environments.
In particular, an array-type airborne RF antenna would likely burst the seals or aperture close-out if built as a sealed internal air volume. Sealed array-type airborne RF antennas can generate pressure differentials between the internal air volume and ambient air, due to the interior air volume and altitude or temperature changes. Therefore, typically an array-type airborne RF antenna may be vented to the ambient air. Such venting facilitates pressure equalization between the internal air volume and ambient air. Unfortunately, when built as a vented air volume, moisture can enter the interior air volume. Therefore, many complex solutions have been used to prevent condensation and/or reduce moisture in the air in the internal air volume of RF antennas of this type. These complex solutions are expensive, unreliable, heavy and/or large, in-efficient, and in general undesirable.
A new device, system and method for moisture and condensation control is now described.